Arrangement for extinguishing electric arcs



April 9, 1940. H. VERSE ARRANGEMENT FOR EXTINGUISHING ELECTRIC ARCSFiled IarCh 7, 1939 Inventor: Hahsh'e'mfich Verse, b .1%

Attorn ey.

Patented Apr. 9, 1940 UNITED STATES ARRANGEMENT FOB EXTINGUISHINGELECTRIC ARCS Hanslseinrich Verse, Brunswick, Germany, aslignor toGeneral Electric Company, a corporation of New York Application March I,1939, Serial No. 260,458

In Germs it, March 17, 1937 4(liaims.

It is known that the arc, arising when the contacts or a switch carryingcontinuous-current are separated, can be extinguished only ii the arcvoltage, requisite to maintain the arc, becomes 5 higher than the supplyvoltage of the network. In order to extinguish the arc in the case of ahigh voltage direct or continuous current the arc must, therefore,either be drawn out to a great length or must be subjected to anextraordinarily strong extinguishing blast.

These methods of extinguishing arcs can be materially improved byfollowing a suggestion, according to which, in order to obtain thepurpose in view, several auxiliary electrodes are provided onto whichthe main arc is blown with the aid of a magnetic field. But apart fromundesired excessive elongation of the arc, as is necessary also withthis switch, the respective arrangement suffers from the drawback thatthe extinguishing effect of the magnetic blow-out depends upon thestrength of the arc current.

It is, furthermore, known that an arc can be extinguished by conductingthrough it a counterdischarge from a condenser for example, theintensity of the current of which is equal to, or greater than, themomentary intensity of the arc to be extinguished. but to produce thiscounterdischarge it has up to now been necessary to make use ofadditional switching arrangements or source of current. If, the netvoltage itself is used for charging the condenser eflecting the counterdischarge it is, if no additional means are employed, possible to attainat the most a strength of counter-current equal to the strength of theinterrupted current, but opposite thereto, but this does not insure thatthe rupturing arc will be reliably and quickly extinguished.

The present invention obviates the above-mentioned disadvantages of theknown arrangements by providing in an arrangement designed forextinguishing arcs with the aid of the dischargecurrent of a condensercharged from the network across a resistance, auxiliary electrodes whichthe arc to be extinguished touches, and which are connected to acondenser charged across high resistances in such a sense that thedischarge initiated by the arc itself extinguishes this arc.

As with the arrangement constituting the present invention theelectro-motive force, driving the counter-current, is always greaterthan the decrease of the counterelectro-motive force of the portion ofthe arc lying in the counter-current circuit, it is, by this inventionassured that a counter-current arises which is essentially greater thanthe current of the arc to be extinguished.

The are current is, therefore, not only reduced to zero in the portionof the arc to be extinguished which is inserted into the counter-currentcircuit, but the counter-current tends to reverse the direction of thecurrent in this position of the arc, 5 that is to say, part of the arcwill be extinguished quickly and definitely where the present improvedarrangement is used.

The invention is illustrated diagrammatically and by way of example onthe accompanying 10 drawing on which Figure 1 is partially an elevation,partially in vertical cross section, of the entire arrangement andcombination of parts constituting the invention, and Figure 2 is ahorizontal cross section through some details located 15 in theuppermost portion oi Figure 1, as more fully described hereinafter.

On the drawing, L denotes a casing of noncombustible or refractorymaterial. This casing may be termed an extinguishing chute. In the 20lowermost portion of said casing or chute are supported two movablecontact members K1 and K: which are located opposite to one another andare intended to interrupt the continuous-current high voltage circuitindicated in Figure 1 by a as heavy line. Into this circuit is inserteda continuous current generator G one pole of which can be grounded aswell as a load V. In the uppermost portion of the casing L are locatedtwo stationary electrode contacts E1 and E: (Figures 1 30 and 2) whichare connected in a circuit network with a condenser C across resistancesR: and R4 of appropriate size. The condenser is charged to the fullvalue of the voltage to be interrupted, in the present case thecontinuous current voltage 36 across resistances R1 and Rs.

If the continuous current circuit is to be interrupted, the two contactsK1 and K: are separated from one another by means of the operatingmechanism denoted H. The are now arising be- 40 tween said contacts iseither blown upwardiy-by a jet of compressed gas, as indicated by theflow direction arrow of Figure 1 from a pipe P connected with a sourceof such gas simultaneously with actuating of the said contacts in themanii ner described, or said are is subjected either to the action of asuitably arranged blowout coil or to the heat generated by the arcitself whereby the arc is driven upward in the casing or chute L. Bysuitably determining the strength of the action IO selected for thepurpose stated it is possible to have the arc touch the electrodes E1and E: only when the contacts K1 and E have been moved away from oneanother to the utmost degree, as indicated by dotted lines in Figure 1.At this 5 moment the condenser C discharges across the portion of theare located between the electrodes E1 and E2 due to the comparativelylow dielectric strength of the are gases in the gap between saidelectrodes, and extinguishes that portion of the arc in said gap, as canbe seen from the signs of polarity and the indications of the directionsin Figure 1. As, owing to the charging path for the condenser C, asstated, there exists always the full operating voltage between theelectrodes E1 and E2, whereas the portion of the are located betweenthese electrodes undergoes only a decrease of voltage, the desiredenforced extinguishing will always take place. The character of thecounter-discharge from the capacity C is to be suitably adjusted bymeans of the resistances R: and R4 or, in lieu thereof, by reactances orby combinations of reactances and resistances.

After the portion of the rupturing are located between the electrodes E1and E2 has been extinguished, the arc portions that existed between thecontact K1 and the electrode E1 and between the contact K2 and theelectrode E: are also extinguished if the resistances R1 and R2 (acrosswhich the condenser C has been charged) are of such high value that thecurrent passing through them becomes so slight that it no longersufilces to maintain an arc whereby the procedure of the self-actingextinguishing is completed The extinguishing method according to thisinvention obviously can also be used for other portions of the are. Butalso any other desired additional extinguishing methods such as fluidblast can be applied to the other portions of the arc.

After the switch has again been closed, the condenser C is againcharged, whereupon the switch is again ready for use, i. e., for anotherinterruption.

The arrangement described is not restricted for the use in connectionwith switches used for the single extinction of arcs, but is alsoapplicable with suitable changes in connection with rectifier devices.

I claim as my invention:

1. An arrangement for extinguishing electric arcs in a direct currentcircuit comprising arcing means connected in said circuit, a pair ofauxiliary electrodes arranged to form an arc gap separate from saidarcing means, means for causing the arc to impinge on said electrodes,and a network including a condenser and impedance electrically connectedto said circuit and to said auxiliary electrodes so that said condenseris charged from said circuit, the connections between said network,auxiliary electrodes and circuit precluding flow of current in the opencircuit position, the polarity of said charge at said electrodes beingopposite to the polarity at said arcing means whereby said condenser candischarge through a portion of said are in opposition to the arc currentwhen said are impinges on said auxiliary electrodes.

2. An arrangement for extinguishing electric arcs in a direct currentcircuit comprising arcing means connected in said circuit, a pair oiauxiliary electrodes forming an arc gap separate and spaced from saidarcing means so that an intermediate portion oi the are when extendedimpinges on said electrodes to bridge said gap, and a condenserelectrically connected to said circuit and across said electrodes sothat the condenser charge across said gap is opposite in polarity tothat at said arcing means whereby said condenser may discharge throughsaid intermediate portion of the arc in opposition to the arc currentwhen said arc moves into the gap between said electrodes.

3. An arrangement for extinguishing electric arcs in a direct currentcircuit comprising separable contacts connected in said circuit, meansfor extending the are beyond said contacts, a pair of electrodes formingan arc gap disposed in the path of said arc so that an intermediateportion of said are can move into said gap to bridge said electrodes,and a circuit network including a con denser and resistanceselectrically connected to said circuit and to said electrodes so thatthe polarity of the condenser charge across said gap is opposite to thatat said contacts whereby said condenser may discharge through saidintermediate arc portion at said gap in opposition to the arc current,said network being connected with respect to said direct current circuitand electrodes so that said condenser is eii'ective to check furthercurrent flow in said circuit after interruption of arcing at saidelectrodes.

4. An arrangement for extinguishing electric arcs in a direct currentcircuit comprising separable contacts connected in said circuit, aninsulating arc chute in which the arc is formed between said contacts,means for directing a fluid blast through said chute for looping saidare beyond said contacts, a pair of auxiliary electrodes disposed insaid chute toward the exhaust portion thereof, said electrodes beingspaced to form a gap directly in the path of an intermediate portion ofsaid arc, and a circuit network including a condenser and resistanceselectrically connected to said circuit and to said auxiliary electrodesso that the polarity of the condenser charge across said gap is oppositeto that at said contacts whereby said condenser may discharge throughsaid gap in opposition to the arc current when said intermediate arcportion moves into said gap, the connections of said network to saiddirect current circuit and auxiliary electrodes being such that saidcondenser precludes further flow of current in said circuit afterinterruption oi the are at said auxiliary electrodes.

HAN SHEINRICH VERSE.

